Electron transport behavior of polymer‐derived amorphous silicoboron carbonitrides

Wang, Kewei; Ma, Baisheng; Zhang, Ligong; Sun, Zhuo; Wang, Yiguang

doi:10.1111/jace.16481

Cited by 16 publications

(2 citation statements)

References 52 publications

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“…[4,61] σ of PDCs pyrolyzed at temperatures below 1300 °C is poor, usually being below 10 −5 S cm −1 at room temperature. [14,20,21,[62][63][64][65][66][67][68][69][70][71][72][73][74] Poor σ limits the functional applications of PDCs. For example, PDCs-based sensors are electrically insulated at room temperature and thus have high sensitivity only at high temperatures.…”

Section: Abnormal Electrical Behaviors In Pdc-sicnmentioning

confidence: 99%

Abnormal Graphitization Behavior in Near‐Surface/Interface Region of Polymer‐Derived Ceramics

Lin

Pan

et al. 2022

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A free carbon phase has been proven to be beneficial for many structural and functional properties of PDCs, such as electrical conductivity, [8][9][10][11][12][13][14] electromagnetic properties, [15][16][17] electrochemical properties, [18,19] piezoelectricity, [20,21] corrosion resistance, [22] and oxidation resistance. [23] In high-temperature sensing applications, the concentration and morphology of free carbon strongly affect the electrical properties of devices and the selectivity/sensitivity of sensors. [4] In energy applications, PDCs are considered promising for electrical energy storage in devices ranging from cell phones to electric cars. [24] The electrical conductivity or free carbon morphology of PDC-based anode materials for lithium ion batteries plays an important role in achieving high reversible capacity, good rate performance, and reliable cycle stability. [25] In electromagnetic wave absorbing and shielding applications, an increase in the free carbon concentration of PDCs leads to an increase in the dielectric loss and, in turn, improves the total shielding effectiveness in terms of both absorption and reflection shielding effectiveness. [26] Therefore, the microstructural evolution of carbon and the properties resulting from the same are of great interest in this research area.This leads to the fundamental and common question of how to effectively regulate the structural evolution of carbon to further enhance the performance of PDCs. The polymer-toceramic transformation process of most PDCs mainly includes the synthesis of a preceramic precursor, shaping, cross-linking, and pyrolysis. [2,27] Amorphous PDCs undergo a devitrification process to form an amorphous multiphase system through a redistribution reaction of chemical bonds under hightemperature conditions. [2,27] The separated free carbon phase undergoes a graphitization process that plays an important role in the microstructural evolution of PDCs. [4] Many studies have claimed that the amount of free carbon within PDCs strongly depends on the thermal stability of the hydrocarbon linkages rather than on the percentage of the total carbon content of the polymer; therefore, a large number of new precursor solutions (e.g., polysiloxane or polysilazane, carbon-rich or carbonpoor polymers) and optimized heat-treatment parameters (e.g., temperature, atmosphere, and holding time) have been designed and explored to improve the graphitization level of The in situ free carbon generated in polymer-derived ceramics (PDCs) plays a crucial role in their unique microstructure and resultant properties. This study advances a new phenomenon of graphitization of PDCs. Specifically, whether in micro-/nanoscale films or millimeter-scale bulks, the surface/interface radically changes the fate of carbon and the evolution of PDC nanodomains, promotes the graphitization of carbon, and evolves a free carbon enriched layer in the near-surface/interface region. Affected by the enrichment behavior of free carbon in the near-surface/interface region, PDCs exhibit h...

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Section: Abnormal Electrical Behaviors In Pdc-sicnmentioning

confidence: 99%

Abnormal Graphitization Behavior in Near‐Surface/Interface Region of Polymer‐Derived Ceramics

Lin

Pan

et al. 2022

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“…Polysiloxane‐derived SiC‐TiC composites are more likely to show even higher electrical conductivity since TiC is more conductive apart from free C and graphitic carbon. Previous studies have demonstrated certain electron transport mechanisms of PDCs, such as a variable‐range hopping mechanism 41 or a band‐tail hopping mechanism 42 for amorphous semiconducting behaviors, and an Arrhenius relationship 41 in the presence of crystalline phases. Thus, the electrical conductivity mechanisms of polymer derived SiC‐TiC should be elucidated in order to provide more guidance for tuning the electrical properties of PDC nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Electrically conductive and thermally stable SiC‐TiC containing nanocomposites via flash pyrolysis

Zheng

2021

J Am Ceram Soc

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Flash pyrolysis, which combines conventional pyrolysis with flash sintering, was first conducted to produce polymer derived SiC‐TiC nanocomposites. Pre‐pyrolysis at 800℃ allows the conversion from titanium isopropoxide (TTIP) modified polysiloxane to an amorphous SiTiOC ceramic. The subsequent application of an electric field gives rise to the formation of turbostratic carbon and creates Joule heating to obtain a sample internal temperature of ~1400℃. The precipitation of β‐SiC, TiC, as well as titanium oxides is realized upon carbothermal reduction of extensively phase separated SiO2 and TiO2 with carbon. Increasing TTIP content embodies the nanocomposites with prominent electrical percolation behaviors. The electrical transport of the synthesized ceramics follows an amorphous semiconductor mechanism. High thermal stability in air is guaranteed, thanks to the in‐situ formed TiC nanocrystals and preferentially reduced amorphous carbon. Flash pyrolyzed nanocomposite with a Ti:Si molar ratio of 0.20 exhibits the highest electrical conductivity (0.696 S/cm) and minimum mass change (~2%) at 1000℃, serving as a competitive candidate for electro‐discharge machining (EDM) applications or self‐standing conducting devices that must withstand high temperature conditions.

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A Review of EPR and Magnetization Investigations of Doped Nanoparticles of Transition Metal Oxides and SiCN: Functional Materials and Spintronic Devices

Misra,

Andronenko

2024

Appl Magn Reson

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Electron transport behavior of polymer‐derived amorphous silicoboron carbonitrides

Cited by 16 publications

References 52 publications

Abnormal Graphitization Behavior in Near‐Surface/Interface Region of Polymer‐Derived Ceramics

Abnormal Graphitization Behavior in Near‐Surface/Interface Region of Polymer‐Derived Ceramics

Electrically conductive and thermally stable SiC‐TiC containing nanocomposites via flash pyrolysis

A Review of EPR and Magnetization Investigations of Doped Nanoparticles of Transition Metal Oxides and SiCN: Functional Materials and Spintronic Devices

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